Coexistence of multiple air interface side-links on a channel

ABSTRACT

Various arrangements for using multiple air interfaces on a frequency channel for side-link communications are presented. A first indication of a first time-window of a first resource pool may be transmitted by a first air interface system. A second indication of a second time-window of a second resource pool may be transmitted by a second air interface system. Side-link communications may be performed using the first air interface during only the first time-window of the first resource pool. Side-link communications may be performed using the second air interface during only the second time-window of the second resource pool.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/277,184, filed Feb. 15, 2019, entitled “Coexistence of Multiple AirInterface Side-links on a Channel,” which is related to U.S. patentapplication Ser. No. 16/277,116, filed Feb. 15, 2019, entitled“Coexistence of Multiple Air Interface Side-links on Adjacent Channels”,the entire disclosures of which are hereby incorporated by reference intheir entirety.

BACKGROUND

Typically, air interface communication protocols, such as 4G LTE and 5GNR are used to communicate between user equipment (UE) and a cellularnetwork base station. However, side-link and device to device (or ProSe)communication is also possible. In side-link communications, vehicle UEcommunicates with another instance of vehicle UE, either directly orwith the assistance of a base station. Similarly, other forms of UE canperform device to device (D2D) or ProSe communication directly or via abase station. Such direct communication may be useful if there is datathat would be useful to transmit to particular instances of UE that arein the immediate vicinity of a transmitting UE.

While such side-link communications may be beneficial in certaininstances, not all UE may use the same air interface communicationprotocol. Therefore, the ability of various instances of UE to coexistmay result in significant inefficiencies, such as different frequencychannels being needed to be allocated to each air interface.

SUMMARY

Various embodiments are described related to a method for using multipleair interfaces on a frequency channel for side-link communications. Insome embodiments, a method for using multiple air interfaces on afrequency channel for side-link communications is described. The methodmay include determining, by an air interface coordination managementserver system, an allocation of a system resource pool among multipledifferent air interfaces such that a first air interface may be assigneda first time-window of a frequency channel of the system resource pooland a second air interface may be assigned a second time-window of thefrequency channel of the system resource pool. The first time-window andthe second time-window may not overlap. The method may includetransmitting a first indication of the first time-window of the systemresource pool to a first air interface system. The method may includetransmitting a second indication of the second time-window of the systemresource pool to a second air interface system. The method may includetransmitting, by the first air interface system, a first indication ofthe first time-window of the system resource pool to a first set of userequipment using the first air interface. The method may includetransmitting, by the second air interface system, a second indication ofthe second time-window of the system resource pool to a second set ofuser equipment using the second air interface. The method may includeperforming, by the first set of user equipment, side-link communicationsusing the first air interface during only the first time-window of thesystem resource pool. The method may include performing, by the secondset of user equipment, side-link communications using the second airinterface during only the second time-window of the system resourcepool.

Embodiments of such a method may include one or more of the followingfeatures: the first air interface may be a 4G LTE air interface. Thesecond air interface may be a 5G NR air interface. The first airinterface may use a first subcarrier spacing and the second airinterface may use a second subcarrier spacing that may be different fromthe first subcarrier spacing. The side-link communications may beselected from a group consisting of vehicle to vehicle communications,vehicle to infrastructure communications, and vehicle to pedestriancommunications. The side-link communications may include basic safetymessages (BSMs). Each BSM may include: vehicle size data, position data,speed data, heading data, acceleration data, and brake system statusdata. The method may further include receiving, by the air interfacecoordination management server system, one or more reports ofcommunication traffic on the first time-window, the second time-window,or both. The method may further include re-determining, by the airinterface coordination management server system, the allocation of thesystem resource pool among multiple different air interfaces based onthe one or more reports of communication traffic. The system resourcepool may periodically repeat. The method may further includetransmitting, by the second air interface system, an indication of asubcarrier spacing to be used during the second time-window of thesystem resource pool to the second set of user equipment using thesecond air interface. No indication of subcarrier spacing may betransmitted to the first set of user equipment using the first airinterface. Subcarrier spacing of the second air interface may bevariable but subcarrier spacing of the first air interface may be fixed.

In some embodiments, a system that uses multiple air interfaces on afrequency channel for side-link communications is described. The systemmay include an air interface coordination management server system thatmay determine an allocation of a system resource pool among multipledifferent air interfaces such that a first air interface may be assigneda first resource pool having a first time-window of a frequency channeland a second air interface may be assigned a second resource pool havinga second time-window of the frequency channel. The system may include afirst air interface system that may receive an indication of the firsttime-window from the air interface coordination management server systemand may transmit the indication of the first time-window to a firstplurality of user equipment that may communicate using the first airinterface. The system may include a second air interface system that mayreceive an indication of the second time-window from the air interfacecoordination management server system and may transmit the indication ofthe second time-window to a second plurality of user equipment that maycommunicate using the second air interface. The system may include thefirst plurality of user equipment that may perform side-linkcommunications using the first air interface during only the firsttime-window of the first resource pool. The system may include thesecond plurality of user equipment that may perform side-linkcommunications using the second air interface during only the secondtime-window of the second resource pool.

Embodiments of such a system may include one or more of the followingfeatures: The first air interface may be a 4G LTE air interface. Thesecond air interface may be a 5G NR air interface. The side-linkcommunications may be selected from a group consisting of vehicle tovehicle communications, vehicle to infrastructure communications, andvehicle to pedestrian communications. The side-link communications mayinclude basic safety messages (BSMs). Subcarrier spacing of the secondair interface may be variable but subcarrier spacing of the first airinterface may be fixed.

In some embodiments, a vehicle system that uses multiple air interfaceson a frequency channel for side-link communications is described. Thesystem may include a first air interface component that may performside-link communications using a first air interface. The system mayinclude a second air interface component that may perform side-linkcommunications using a second air interface. The system may include avehicle systems interface. The system may include one or more processorsconfigured to receive one or more resource pool allocation messages viathe first air interface component, the second air interface component,or both. The one or more resource pool allocation messages may allocatea system resource pool among multiple different air interfaces such thatthe first air interface may be assigned a first resource pool having afirst-time-window of a frequency channel and the second air interfacemay be assigned a second resource pool having second time-window of thefrequency channel. The system may schedule a first side-linkcommunication using the first air interface component and the first airinterface during the first time-window on the frequency channel. Thesystem may schedule a second side-link communication using the secondair interface component and the second air interface during the secondtime-window on the frequency channel. The system may perform the firstside-link communication during the first time-window on the frequencychannel. The first side-link communication may use data obtained fromthe vehicle systems interface. The system may perform the secondside-link communication during the second time-window on the frequencychannel. The second side-link communication may use data obtained fromthe vehicle systems interface.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of variousembodiments may be realized by reference to the following figures. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 illustrates multiple resource pools that are configured to allowfor coexistence of multiple air interfaces on the same channel.

FIG. 2 illustrates a system that uses multiple air interfaces forside-link communications using a resource pool.

FIG. 3 illustrates an embodiment of a vehicle system that cancommunicate using multiple air interfaces using a same resource pool.

FIG. 4 illustrates an embodiment of a method for using multiple airinterfaces on a same resource pool for side-link communications.

FIG. 5 illustrates an embodiment of a method for a vehicle system usingmultiple air interfaces on a same resource pool for side-linkcommunications.

DETAILED DESCRIPTION OF THE INVENTION

Various air interfaces describe the ability of UE to communicate usingside-links. A side-link can refer to a direct wireless communicationbetween two instances of vehicle UE with or without using a cellularnetwork base station. Such a side-link may be autonomous (radioresources are chosen for the side-link communication without schedulingfrom the base-station), or scheduled by the base-station (thebase-station assigns the resources for the communication and the UEsreceive messages indicating as such). Vehicle communication systems maybe built into a vehicle (e.g., car, truck, motorcycle, scooter, train,boat, tram, subway, etc.). Typically, such as defined by 3GPP, side-linkcommunications refer to vehicle-to-vehicle (V2V) side-linkcommunications; however, other forms of communication may also beconsidered a form of side-link communication, such asvehicle-to-infrastructure (V2I) side-link communications andvehicle-to-pedestrian (V2P) communications. Infrastructure UE may beinstalled at various pieces of infrastructure, such as brides, roadways,highways, traffic lights, buildings, parking facilities, etc. Pedestriancommunication systems may include mobile devices, such as smartphones,that a pedestrian may carry on his body.

Such side-link communications may allow for safety information to bequickly and efficiently exchanged between UE located in the vicinity ofeach other. For example, side-link communications may typically beperformed over distances of 1000 feet or less. Such side-linkcommunications may involve basic safety messages (BSMs) beingtransmitted and received via side-link communications. BSMs may includedata such as: a timestamp; position (latitude, longitude, elevation);speed; heading; acceleration; brake system status; vehicle size;steering wheel angle; positional accuracy; braking history; pathprediction; throttle position; vehicle mass; trailer weight; vehicletype; vehicle description; anti-lock brake system (ABS) status; tractioncontrol status; stability control status; differential GPS; lightsstatus; wiper status; brake level; coefficient of friction; rain type;air temperature; air pressure; vehicle identification; cargo weight; andGPS status. Such data may be transmitted via a side-link using an airinterface to other instances of UE in the immediate vicinity.

In order to successfully communicate using a side-link communication,the same air interface needs to be used by the transmitting UE and thereceiving UE. For example, side-link communications may use 4G LTE (LongTerm Evolution) as the air interface communication protocol or may use5G NR (New Radio) as the air interface communication protocol. Aninstance of user equipment may, for example, be able to communicate:using only 4G LTE; using only 5G NR; or using both air interfacecommunication protocols. It can be expected that 5G NR UE will becompatible with 4G LTE. Other air interface communication protocols mayalso be possible.

Side-links performed using air interfaces that use differentcommunication protocols (such as 4G LTE and 5G NR) may be performedusing the same frequency channel. Since different air interfacecommunication protocols are incompatible, interference is possible. Forexample, different air interface communication protocols may usedifferent subcarrier spacing; thus, interference could result due to thelack of orthogonality if both air interfaces were used for communicationon the same resource pool. As a specific example, 4G LTE only uses 15KHz subcarrier spacing; however, 5G NR uses multiple differentsubcarrier spacings (15 KHz, 30 KHz, 60 KHz, etc.) to be used. However,multiple air interface communication protocols can share a samefrequency channel for side-link communications as detailed herein by thefrequency channel being subdivided based on time.

FIG. 1 illustrates multiple resource pools that are configured to allowfor coexistence of multiple air interfaces on the same channel. A systemresource pool 100 can be subdivided in the frequency domain into varioussubcarriers having various subcarrier spacings. System resource pool 100may also be defined over a period of time. After the period of time, anew system resource pool may be present, allowing for periodicrepetition of system resource pool 100.

System resource pool 100 is divided, based on time, into a first airinterface side-link resource pool 110 and a second air interfaceside-link resource pool 120. For example, the first air interface may be4G LTE and the second air interface may be 5G NR. First air interfaceside-link resource pool 110 and second air interface side-link resourcepool 120 each include the entire frequency channel. First air interfaceside-link resource pool 110 occurs over first time period 111 and secondair interface side-link resource pool 120 occurs over second time period121. The first time period 111 and the second time period 121 can beadjacent, but do not overlap. The relative duration of first airinterface side-link resource pool 110 and second air interface side-linkresource pool 120 may be varied based on the measured or expected amountof traffic using each air interface communication protocol. As seen inFIG. 1, first time period 111 is shorter in duration than second timeperiod 121. Therefore, it can be expected that fewer side-linkcommunications using the first air interface have previously beenpresent or are expected to be present than via the second air interface.In other embodiments, a predefined fixed allocation of system resourcepool 100 may be performed between the first air interface and the secondair interface.

Even though first air interface side-link resource pool 110 and secondair interface side-link resource pool 120 are part of the same frequencychannel, since time division of system resource pool 100 is used,different subcarrier spacing or the same subcarrier spacing may be usedfor each pool without interference. For example, if the first airinterface is 4G LTE, the subcarrier spacing can only be at 15 kHz. Ifthe second air interface is 5G NR, the subcarrier spacing may be set toeither, for example, 15 kHz, 30 kHz, 60 kHz in a first frequency range(FR1) or 60 kHz or 120 kHz in a second frequency range (FR2). To changethe subcarrier spacing, side-link resource pool 120 may need to bereconfigured.

Each instance of UE may receive data that indicates how system resourcepool 100 is apportioned. Therefore, a UE can schedule side-linkcommunications during first time period 111 if the first air interfaceis to be used or during second time period 121 if the second airinterface is to be used. While the illustrated example illustratessystem resource pool 100 being divided into more than two resource poolsto accommodate more than two air interface communication protocols.

FIG. 2 illustrates a system 200 that uses multiple air interfaces forside-link communications using a resource pool. System 200 may include:coordination management system 210; first air interface control system220; second air interface control system 230; base station 222; basestation 232; pedestrian UE 250 (which is represented on FIG. 2 as apedestrian holding a UE); vehicles 240 (240-1, 240-2, 240-3); andinfrastructure 260.

Coordination manager system 210 can represent one or more server systemsthat can either statically, semi-statically or dynamically subdivideside-link resource pools (e.g., system resource pool 100) into one ormore resource pools for different air interfaces. Coordination managersystem 210 may be operated by a particular cellular network provider ormay be used to coordinate resource pools across multiple cellularnetwork service providers. If coordination manager system 210 isoperated by a particular cellular network provider, it may be incommunication with a master coordination system that communicates withcoordination manager systems operated by multiple cellular networkproviders or coordination manager system 210 may communicate withcoordination manager systems operated by other cellular serviceproviders such that the side-link resource pools are dividedconsistently across service providers in a given geographic region (thusallowing for communication among UE of different service providers).Coordination manager system 210 may assign a portion of a resource poolto each air interface.

In some embodiments, a static amount of resource pool is assigned toeach air interface. A static amount of resource pool may be assignedonce and remain fixed. In a semi-static arrangement, the semi-staticamount may be occasionally or periodically reassessed, such as daily orweekly. For example, half of a resource pool may be assigned to a firstair interface and the second half of the resource pool may be assignedto the second air interface. In some embodiments, a dynamic amount ofresource pool is assigned to each air interface. In such embodiments,coordination manager system 210 may have a traffic analysis system 212.Traffic analysis system 212, which may be special-purpose computerhardware or a software process executed by coordination manager system210, may receive indications of side-link traffic. Based on analyzingthe amount of side-link traffic or the amount of collisions in side-linktraffic, coordination manager system 210 may adjust the allocation ofthe amount of resource pools that are assigned to each air interface.For example, if a large amount of side-link traffic is present using afirst air interface but a relatively little amount of side-link trafficis present using a second air interface, allocation of resource poolsmay be adjusted such that the first air interface is allocated a greaterportion of each resource pool. Such an adjustment may occur on ageographic basis; that is, certain geographic regions may see one airinterface being allocated a greater portion of each resource pool whileanother geographic region may see a different air interface beingallocated a greater portion of each resource pool.

Coordination manager system 210 may communicate with first air interfacecontrol system 220 and second air interface control system 230. Firstair interface control system 220 and second air interface control system230 can represent control systems that are part of wireless networksthat use different air interface communication protocols. By way ofexample, first air interface control system 220 may use 4G LTE as itsair interface communication protocol and second air interface controlsystem 230 may use 5G NR as its air interface communication protocol.First air interface control system 220 and second air interface controlsystem 230 may receive indications of the time window of side-linkresource pools that are allocated to the air interface used by theparticular control system. The time window available for use forside-link communications for each particular air interface may becommunicated by the control system, through a base station, to eachinstance of UE with which the base station is in communication. Forexample, first air interface control system 220 may transmit anindication of the time window of each resource pool during whichside-link communication using the first air interface is permitted viabase station 222 to instances of UE that communicate using the first airinterface and are in communication with base station 222. Similarly, forexample, second air interface control system 230 may transmit anindication of the time window of each resource pool during whichside-link communication using the second air interface is permitted viabase station 232 to instances of UE that communicate using the secondair interface and are in communication with base station 232. In otherembodiments, the indication may include more information, such asindicating the particular air interface that is allocated to each timewindow within each resource pool. Therefore, in such embodiments, a UEthat communicates using multiple air interfaces could determine when itcan transmit a side-link communication using the second air interfacebased on an indication received from first air interface control system220 through base station 222.

In system 200, for example, the first air interface may be 4G LTE. Insuch an embodiment, base station 222 may be an eNodeB. First airinterface control system 220 may be part of the enhanced packet core(EPC) of the 4G LTE network or may be incorporated as part of theeNodeB. The second air interface may be 5G NR. In such an embodiment,base station 232 may be a gNodeB. Second air interface control system230 may be part of the core 5G network or may be incorporated as part ofthe gNodeB.

In system 200, pedestrian UE 250, vehicle 240-3, vehicle 240-2, andvehicle 240-1 communicate using the first air interface; vehicle 240-1,and infrastructure 260 communicate using the second air interface.Pedestrian UE 250 communicates with base station 222 via wireless link270; vehicle 240-3 communicates with base station 222 via wireless link271; vehicle 240-2 communicates with base station 222 via wireless link272; and vehicle 240-1 communicates with base station 222 via wirelesslink 279. Vehicle 240-1 communicates with base station 232 via wirelesslink 275; vehicle 240-2 communicates with base station 232 via wirelesslink 280; and infrastructure 260 communicates with base station 232 viawireless link 276. In system 200, side-link communications may be in theform of broadcast messages or messages transmitted to specific otherinstance of UE in the vicinity. Various side-link communications arepresent: side-link 273 (which is vehicle-to-pedestrian); side-link 278(which is vehicle-to-vehicle); and side-link 274 (which isvehicle-to-vehicle). In some embodiments, another form of direct orindirect communication may be present, such as side-link 277 (which isvehicle-to-infrastructure).

Side-link 273 may be performed using the first air interface using theportion of resources for side-links assigned to the first air interface,such as first air interface side-link resource pool 110. Side-link 278may also be performed using the first air interface using the portion ofthe resources for side-links assigned to the first air interface.However, vehicle 240-2 may have UE that is also capable of communicatingusing the second air interface. Side-link 274 may be performed using thesecond air interface using the portion of resources for side-linksassigned to the second air interface, such as second air interfaceside-link resource pool 120. Side-link 277 may also be performed usingthe second air interface using the portion of resources for side-linksassigned to the second air interface. In some embodiments, data aboutside-link communications may be reported back to first air interfacecontrol system 220, second air interface control system 230, or both.Such data about side-link communications may indicate: 1) that suchside-link transmissions have occurred; and/or 2) that side-linktransmission collisions occurred. Such data may be reported back tocoordination manager system 210 for use by traffic analysis system 212.

FIG. 3 illustrates an embodiment of a vehicle system 300 that cancommunicate using multiple air interfaces using a same resource forside-links. An embodiment of vehicle system 300 may be present onvehicle 240-1 and 240-2. On vehicle 240-3, an embodiment of vehiclesystem 300 may present that does not include second air interfacecomponent 330. Vehicle system 300 can include: vehicle processing system310; first air interface component 320; second air interface component330; vehicle systems interface 340; and vehicle systems 350 (which caninclude GPS module 352, steering system 354, braking system 356, andfixed vehicle datastore 358).

Vehicle processing system 310 may include one or more special-purpose orgeneral-purpose processors. Such special-purpose processors may includeprocessors that are specifically designed to perform the functionsdetailed herein. Such special-purpose processors may be ASICs(application-specific integrated circuits) or FPGAs (field-programmablegate arrays) which are general-purpose components that are physicallyand electrically configured to perform the functions detailed herein.Such general-purpose processors may execute special-purpose softwarethat is stored using one or more non-transitory processor-readablemediums, such as random access memory (RAM), flash memory, a hard diskdrive (HDD), or a solid state drive (SSD). The various components ofvehicle processing system 310 may be implemented using such special- orgeneral-purpose processors.

Vehicle processing system 310 may be in communication with first airinterface component 320, second air interface component 330, or both.First air interface component 320 may transmit and receive data with acellular network that uses the first air interface and may performside-link communications with other instances of UE that communicateusing the first air interface. Second air interface component 330 maytransmit and receive data with a cellular network that uses the secondair interface and may perform side-link communications with otherinstances of UE that communicate using the second air interface. In someexamples, first air interface component 320 communicates using 4G LTEand second air interface component communicates using 5G LTE. It shouldbe understood that in other embodiments a greater number (or fewernumber) of air interface components may be present.

Vehicle processing system 310 may store side-link resource poolallocation data received via first air interface component 320, secondair interface component 330, or both in air interface configuration data314. This data may be accessed by side-link communication scheduler 316to determine which portion of a resource pool has been allocated forside-link communications in the air interface that is to be used for theside-link communication. Side-link communication scheduler 316 may causethe side-link communication to be transmitted as one or more packetsduring one or more appropriate sub-pools across one or more side-linkcommunication resource pools.

Vehicle data compiler and analyzer 312 may: 1) receive and format dataobtained from vehicle systems interface 340 for transmission in the formof one or more messages, such as BSMs; and 2) interpret messages, suchas BSMs, received from other instances of UE via side-linkcommunications. Vehicle systems interface 340 may collect data fromvarious vehicle systems 350. For example, such vehicle systems caninclude: GPS module 352 (e.g., location, elevation, position accuracy);steering system 354 (e.g., steering angle); braking system 356 (e.g.,whether or not engaged, amount of braking); and fixed vehicle datastore358 (e.g., data about the vehicle that does not regularly change, suchas vehicle type, vehicle description, etc.). In some embodiments,vehicle systems 350 may communicate directly with vehicle processingsystem 310. In other embodiments, other vehicle systems may provide datafor inclusion in BSMs or other forms of data transmissions viaside-links.

BSMs or other types of messages may be broadcast via side-linkcommunications or may be transmitted to particular other instances ofUE. In a broadcast form, any instance of UE in the vicinity (withinreception range) that communicates using the air interface used totransmit the side-link communication may be able to receive theside-link communication to determine where the instance of UE islocated. In an embodiment such as illustrated of vehicle system 300,both first air interface component 320 and second air interfacecomponent 330 may be used to transmit similar data as side-linkcommunications using different air interfaces and the assigned sub-poolsof resource pools.

Similar systems to vehicle system 300 may be present in pedestrian UEand infrastructure UE to transmit via side-link transmissions theposition and state of the instance of UE and to receive and analyzeside-link communications received from other instances of UE.

Various methods may be performed using the systems detailed in FIGS. 2and 3 and the resource pool allocation detailed in relation to FIG. 1.FIG. 4 illustrates an embodiment of a method 400 for using multiple airinterfaces on a same resource pool for side-link communications. Method400 may be performed using at least some components of system 200 ofFIG. 2. In other embodiments, method 400 may be performed using a systemother than system 200 of FIG. 2.

At block 405, a determination that a system resource pool is to bedivided up between multiple air interfaces may be made. In someembodiments, this determination may not be necessary because theresource pools are always allocated among multiple air interfaces. Inother embodiments, a system, such as a coordination manager system, maydetermine that based on various parameters, such as the instances ofuser equipment in a particular region, that resource pools available forsite links are to be allocated among multiple air interfaces. While morethan two air interfaces may be used in conjunction with a resource poolfor single frequency channel, the remainder of the example of method 400assumes that the resource pool is being allocated for two airinterfaces. For example, the first air interface may be 4G LTE and thesecondary interface may be 5G NR.

At block 410, a determination may be made about how resource pools areto be allocated among multiple air interfaces. The allocation may bebased on a time window of the entire frequency channel of the resourcepool being assigned to each air interface. Therefore, the greater thepercent that the time window is of the entire resource pool, the greaterthe available bandwidth for transmitting side-link messages using theassociated air interface. The determination of block 410 may beperformed by a coordination manager system. The determination may bebased on the determined or expected amount of side-link traffic usingeach air interface among which the system resource pool is beingallocated.

At block 415, an indication may be provided to a first air interfacesystem of a time-window for side-link resource pools that has beenallocated to the first air interface. The indication may indicate astart time and end time of the time-window of each resource pool.Similarly, at block 420, an indication may be provided to a second airinterface system of a second, non-overlapping time-window for side-linkresource pools that has been allocated to the second air interface. Theindication may indicate a start time and end time of the secondtime-window of each resource pool. These indications may be provided bythe coordination manager system. The duration of each time-window may bebased on the determination of block 410.

At block 425, an indication of the first time-window of the resourcepools that are allocated for side-link transmissions using the first airinterface may be transmitted to UE that is communicating with the firstair interface system. Such an indication may be transmitted in only aparticular geographic region or in certain cells of the cellularnetwork. In response to the indication, each UE which receives themessage may update stored air interface configuration data that isstored locally. In an example in which the first air interface is 4GLTE, no indication of a subcarrier spacing may be transmitted sincesubcarrier spacing for side-link communications may be fixed. At block430, an indication of the second time-window of the resource pools thatare allocated for side-link transmissions using the second air interfacemay be transmitted to UE that is communicating with the second airinterface system. Such an indication may be transmitted in only aparticular geographic region or in certain cells of the cellularnetwork. In response to the indication, each UE which receives themessage may update stored air interface configuration data that isstored locally. In an example in which the second air interface is 5GNR, an indication of subcarrier spacing may also be transmitted sincesubcarrier spacing for 5G NR side-link communications may be variablebased on the network configuration. Therefore, the subcarrier spacing ofthe second pool may differ

At block 435, side-link communications may be performed directly betweenUE using the first time-window for the first air interface and thesecond time-window for the second air interface. By using differenttime-windows of each resource pool, different air interfaces can use thesame frequency channel. Side-link communications may be sent in the formof a broadcast message that can be received directly by multipleinstances of UE located within communication range or may be sent as amessage addressed to a particular instance of UE. At block 440, in someembodiments, side-link communication messages or collisions may bereported back via the first air interface system, the second airinterface system, or both such that the allocation of the resource poolcan be adjusted to better accommodate the side-link communicationtraffic.

While method 400 is focused on actions that are taken at a system level,method 500 is focused on actions performed by an instance of UE, such asa vehicle-based system. FIG. 5 illustrates an embodiment of a method 500for a vehicle system using multiple air interfaces on a same resourcepool for side-link communications. Method 500 may be performed usingvehicle system 300. Method 500 may alternatively be performed using somealternate form of UE.

At block 505, an instance of UE may receive one or more resource poolallocation messages. A resource pool allocation message may indicate atime window within side-link system resource pools allocated to the airinterface particular corresponding to the air interface system fromwhich the message was received. Alternatively, the resource poolallocation message may indicate how the resource pool is allocated as awhole. (Thus, it may be possible for an instance of UE to receive aresource pool message via a first air interface and send a side-linkcommunication using a second air interface during the correct poolassigned to the second air interface.)

At block 510, based on the received one or more resource pool allocationmessages, a side-link communication message may be scheduled fortransmission using the first air interface during a first time-window orfirst resource pool assigned to the first air interface. Similarly, ifthe UE also has an air interface component that communicates using thesecond air interface, At block 515, based on the received one or moreresource pool allocation messages, a different side-link communicationmessage may be scheduled for transmission using the second air interfaceduring a second time-window or second resource pool assigned to thesecond air interface. Therefore, while the first side-link message andthe second side-link message may contain the same or similar data, theymay be sent using different protocols and carrier spacing during theappropriate assigned resource pool time-windows. At block 520 and 525,the first side-link communication and the second side-link communicationmay be transmitted. At block 520, the first side-link communication maybe transmitted using the first air interface to a first UE using a firstsubcarrier spacing during the first time-window. At block 525, thesecond side-link communication may be transmitted using the second airinterface to a second UE using a second subcarrier spacing during thesecond time-window.

While method 500 is directed to transmitting side-link messages, asimilar scheduled arrangement can also be used for receiving side-linkmessages. That is, during the pool or time-window assigned to the firstair interface, side-link messages in the first air interfacecommunication protocol are listened for and received on the frequencychannel; and during the second pool or second time-window assigned tothe second air interface, side-link messages in the second air interfacecommunication protocol are listened for and received on the frequencychannel.

In the example of method 500, the UE communicates using both airinterfaces. If UE uses the second air interface, it may be backwardscompatible to use the first air interface. In other embodiments, someinstances of UE may exclusively use the first air interface or thesecond air interface. In other embodiments, a greater number of airinterfaces may be used and the resource pool may be further subdividedto accommodate more than two air interfaces.

The methods, systems, and devices discussed above are examples. Variousconfigurations may omit, substitute, or add various procedures orcomponents as appropriate. For instance, in alternative configurations,the methods may be performed in an order different from that described,and/or various stages may be added, omitted, and/or combined. Also,features described with respect to certain configurations may becombined in various other configurations. Different aspects and elementsof the configurations may be combined in a similar manner. Also,technology evolves and, thus, many of the elements are examples and donot limit the scope of the disclosure or claims.

Specific details are given in the description to provide a thoroughunderstanding of example configurations (including implementations).However, configurations may be practiced without these specific details.For example, well-known circuits, processes, algorithms, structures, andtechniques have been shown without unnecessary detail in order to avoidobscuring the configurations. This description provides exampleconfigurations only, and does not limit the scope, applicability, orconfigurations of the claims. Rather, the preceding description of theconfigurations will provide those skilled in the art with an enablingdescription for implementing described techniques. Various changes maybe made in the function and arrangement of elements without departingfrom the spirit or scope of the disclosure.

Also, configurations may be described as a process which is depicted asa flow diagram or block diagram. Although each may describe theoperations as a sequential process, many of the operations can beperformed in parallel or concurrently. In addition, the order of theoperations may be rearranged. A process may have additional steps notincluded in the figure. Furthermore, examples of the methods may beimplemented by hardware, software, firmware, middleware, microcode,hardware description languages, or any combination thereof. Whenimplemented in software, firmware, middleware, or microcode, the programcode or code segments to perform the necessary tasks may be stored in anon-transitory computer-readable medium such as a storage medium.Processors may perform the described tasks.

Having described several example configurations, various modifications,alternative constructions, and equivalents may be used without departingfrom the spirit of the disclosure. For example, the above elements maybe components of a larger system, wherein other rules may takeprecedence over or otherwise modify the application of the invention.Also, a number of steps may be undertaken before, during, or after theabove elements are considered.

What is claimed is:
 1. A method for accommodating multiple airinterfaces for side-link communications, the method comprising:determining, by an air interface coordination management system, anallocation of a system resource pool among multiple different airinterfaces such that a first air interface is assigned a firsttime-window of a frequency channel of the system resource pool forcommunication with a first set of user equipment, wherein: the airinterface coordination management system is in communication with afirst air interface control system that manages communication with thefirst set of user equipment via the first air interface and is incommunication with a second air interface control system that managescommunication with a second set of user equipment via a second airinterface; the second air interface has a second time-window of thefrequency channel of the system resource pool for communication with thesecond set of user equipment; the first time-window and the secondtime-window do not overlap; and the system resource pool periodicallyrepeats; providing, by the air interface coordination management system,a first indication of the first time-window of the system resource poolto the first air interface control system, wherein: the first airinterface control system is in communication with a first cellularnetwork that uses the first air interface; providing, by the airinterface coordination management system, a second indication of thesecond time-window of the system resource pool to the second airinterface control system; and transmitting, by the first air interfacecontrol system, the first indication of the first time-window of thesystem resource pool to the first set of user equipment using the firstair interface via the first cellular network, wherein: the first set ofuser equipment perform side-link communications using the first airinterface during only the first time-window of the system resource pool.2. The method for accommodating multiple air interfaces for side-linkcommunications of claim 1, wherein the first air interface is a 4G LTEair interface.
 3. The method for accommodating multiple air interfacesfor side-link communications of claim 1, wherein the first air interfaceis a 5G NR air interface.
 4. The method for accommodating multiple airinterfaces for side-link communications of claim 1, wherein the firstair interface uses a first subcarrier spacing and the second airinterface uses a second subcarrier spacing that is different from thefirst subcarrier spacing.
 5. The method for accommodating multiple airinterfaces for side-link communications of claim 1, wherein theside-link communications are selected from a group consisting of:vehicle-to-vehicle communications; vehicle-to-infrastructurecommunications; and vehicle-to-pedestrian communications.
 6. The methodfor accommodating multiple air interfaces for side-link communicationsof claim 1, wherein the side-link communications comprise basic safetymessages (BSMs).
 7. The method for accommodating multiple air interfacesfor side-link communications of claim 6, wherein each BSM comprises:vehicle size data, position data, speed data, heading data, accelerationdata, and brake system status data.
 8. The method for accommodatingmultiple air interfaces for side-link communications of claim 1, furthercomprising: receiving, by the air interface coordination managementsystem, a communication traffic report about the first time-window. 9.The method for accommodating multiple air interfaces for side-linkcommunications of claim 8, further comprising: re-determining, by theair interface coordination management system, the allocation of thesystem resource pool among multiple different air interfaces based atleast in part on the communication traffic report.
 10. The method foraccommodating multiple air interfaces for side-link communications ofclaim 1, further comprising: transmitting, by the first air interfacecontrol system, an indication of a subcarrier spacing to be used duringthe first time-window of the system resource pool to the first set ofuser equipment using the first air interface.
 11. The method foraccommodating multiple air interfaces for side-link communications ofclaim 1, wherein subcarrier spacing of the first air interface isvariable but subcarrier spacing of the second air interface is fixed.12. A system that accommodating multiple air interfaces for side-linkcommunications, the system comprising: an air interface coordinationmanagement server system that determines an allocation of a systemresource pool among multiple different air interfaces such that a firstair interface is assigned a first resource pool having a firsttime-window of a frequency channel, wherein: the air interfacecoordination management server system is in communication with a firstair interface control system that manages communication with a first setof user equipment via the first air interface and is in communicationwith a second air interface control system that manages communicationwith a second set of user equipment via a second air interface; thesecond air interface has a second resource pool having a secondtime-window of the frequency channel; the air interface coordinationmanagement server system provides a second indication of the secondtime-window of the system resource pool to the second air interfacecontrol system; the first time-window and the second time-window do notoverlap; and the system resource pool periodically repeats; and thefirst air interface control system that receives an indication of thefirst time-window from the air interface coordination management serversystem and transmits, via a first cellular network, the indication ofthe first time-window to a first plurality of user equipment thatcommunicate using the first air interface, wherein: the first pluralityof user equipment that perform side-link communications using the firstair interface during only the first time-window of the first resourcepool.
 13. The system that accommodates multiple air interfaces forside-link communications of claim 12, wherein the first air interface isa 4G LTE air interface.
 14. The system that accommodates multiple airinterfaces for side-link communications of claim 12, wherein the firstair interface is a 5G NR air interface.
 15. The system that accommodatesmultiple air interfaces for side-link communications of claim 12,wherein the side-link communications are selected from a groupconsisting of: vehicle-to-vehicle communications;vehicle-to-infrastructure communications; and vehicle-to-pedestriancommunications.
 16. The system that accommodates multiple air interfacesfor side-link communications of claim 15, wherein the side-linkcommunications comprise basic safety messages (BSMs).
 17. The systemthat accommodates multiple air interfaces for side-link communicationsof claim 12, wherein subcarrier spacing of the first air interface isvariable but subcarrier spacing of the second air interface is fixed.18. The system that accommodates multiple air interfaces for side-linkcommunications of claim 12, wherein subcarrier spacing of the first airinterface is fixed but subcarrier spacing of the second air interface isvariable.
 19. A vehicle system that accommodates multiple air interfacesfor side-link communications, the vehicle system comprising: a first airinterface component that performs side-link communications using a firstair interface; a second air interface component that performs side-linkcommunications using a second air interface; a vehicle systemsinterface; and one or more processors, configured to: receive a resourcepool allocation message via the first air interface component, wherein:the resource pool allocation message allocates a system resource poolamong multiple different air interfaces such that the first airinterface is assigned a first resource pool having a first time-windowof a frequency channel; the second air interface has a second resourcepool having second time-window of the frequency channel; an airinterface coordination management system is in communication with afirst air interface control system that manages communication with thefirst air interface component via the first air interface; the firsttime-window and the second time-window do not overlap; and the systemresource pool periodically repeats; schedule a first side-linkcommunication using the first air interface component and the first airinterface during the first time-window on the frequency channel; andperform the first side-link communication during the first time-windowon the frequency channel, wherein the first side-link communication usesdata obtained from the vehicle systems interface.
 20. The vehicle systemthat accommodates multiple air interfaces for side-link communicationsof claim 19, wherein the first air interface is a 4G LTE air interfaceor the first air interface is a 5G NR air interface.